Viral epidemiology and severity of respiratory infections in infants in 2009: a prospective study.
ABSTRACT Viral respiratory infections are common in infants and can be severe. The new pandemic influenza virus H1N1v2009 was feared to cause particularly severe outcomes.
This study aimed at evaluating the impact of H1N1v2009 on the viral epidemiology, the clinical presentation and the severity of respiratory infections in infants.
This prospective epidemiologic study included all infants <2 years of age, both inpatients and outpatients, presenting with respiratory symptoms, from November 2009 through April 2010, at the pediatric emergency department of the University Hospital of Caen, France. A nasal swab was taken for viral detection and analyzed by immunofluorescence and, if negative, polymerase chain reaction. Severe respiratory infection was defined by a score of respiratory severity.
One thousand twenty-one infectious episodes with a respiratory sample met inclusion criteria. Eight hundred thirty-four samples (81.7%) were positive. The viruses with the highest incidence were the respiratory syncytial virus (34.2%), the rhinoviruses (23.9%), the coronaviruses (9.3%) and H1N1v2009 (7.7%). Of all infections, 28.6% were severe and more frequent in infants with risk factors. H1N1v2009 infections had a low risk of severe respiratory disease (odds ratios = 0.15) and hospitalization (odds ratios = 0.40) compared with the other viruses. Respiratory syncytial virus infections had a high risk of respiratory severity (odds ratios = 7.85) and were responsible for 71.4% of admissions to the intensive care unit.
Despite the modest impact of H1N1v2009 observed in this study, further surveillance is needed to detect virological factors that may increase its severity.
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ABSTRACT: Although acute respiratory illnesses (ARI) are major causes of morbidity and mortality in early childhood worldwide, little progress has been made in their control and prophylaxis. Most studies have focused on hospitalized children or children from closed populations. It is essential that the viral etiology of these clinical diseases be accurately defined in the development of antiviral drugs. To investigate the role of all common respiratory viruses as upper and lower respiratory tract pathogens in the first year of life. This community-based birth cohort study prospectively collected detailed information on all ARI contracted by 263 infants from birth until 1 year of age. Nasopharyngeal aspirates were collected for each ARI episode, and all common respiratory viruses were detected by polymerase chain reaction. Episodes were classified as upper respiratory illnesses or lower respiratory illnesses (LRI), with or without wheeze. The majority reported 2-5 episodes of ARI in the first year (range, 0-11 episodes; mean, 4.1). One-third were LRI, and 29% of these were associated with wheeze. Viruses were detected in 69% of ARI; most common were rhinoviruses (48.5%) and respiratory syncytial virus (RSV) (10.9%). Compared with RSV, >10 times the number of upper respiratory illnesses and >3 times the number of both LRI and wheezing LRI were attributed to rhinoviruses. Rhinoviruses are the major upper and lower respiratory pathogens in the first year of life. Although RSV is strongly associated with severe LRI requiring hospitalization, the role of rhinoviruses as the major lower respiratory pathogens in infants has not previously been recognized.The Pediatric Infectious Disease Journal 08/2006; 25(8):680-6. · 3.57 Impact Factor
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ABSTRACT: Respiratory virus infections are the most important trigger of respiratory illnesses in childhood. Data on the occurrence and the clinical impact of respiratory pathogens in the general population of infants are scarce. Therefore, we described the occurrence and clinical impact of respiratory pathogens in infants with respiratory tract infections during the first year of life. In a prospective birth cohort study, infants were followed from birth through the first year of life with daily questionnaires about respiratory symptoms. Nose and throat swabs were collected during episodes with respiratory symptoms. Polymerase chain reaction was used to detect an extensive panel of respiratory pathogens. The parents reported a median of 5 respiratory episodes per infant per year. A total of 668 respiratory samples were collected in 305 infants. One or more respiratory pathogens were detected in 85% of the samples. The most common respiratory pathogens were human rhinovirus (HRV) (73% of the samples), respiratory syncytial virus (RSV) (11%), and coronavirus (8%). HRV infections were associated with a prolonged period of symptoms compared with RSV (P = 0.03). Infections with RSV were associated with more physician visits than HRV infections (P = 0.06). We found a high prevalence of respiratory pathogens among infants with parent-reported respiratory illnesses in the first year of life, with HRV being the most prevalent. Although RSV infections seemed to be responsible for the most severe symptoms compared with HRV, the overall burden of disease was highest for HRV infections.The Pediatric Infectious Disease Journal 07/2009; 28(6):472-6. · 3.57 Impact Factor
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ABSTRACT: Acute respiratory infections (ARI) are a major cause of morbidity in infancy worldwide, with cough and wheeze being alarming symptoms to parents. We aimed to analyze in detail the viral aetiology of ARI with such symptoms in otherwise healthy infants, including rhinoviruses and recently discovered viruses such as human metapneumovirus (HMPV), coronavirus NL63 and HKU1, and human bocavirus (HBoV). We prospectively followed 197 unselected infants during their first year of life and assessed clinical symptoms by weekly standardized interviews. At the first ARI with cough or wheeze, we analyzed nasal swabs by sensitive individual real time polymerase chain reaction assays targeting 16 different respiratory viruses. All 112 infants who had an ARI had cough, and 39 (35%) had wheeze. One or more respiratory viruses were found in 88 of 112 (79%) cases. Fifteen (17%) dual and 3 (3%) triple infections were recorded. Rhino- (23% of all viruses) and coronaviruses (18%) were most common, followed by parainfluenza viruses (17%), respiratory syncytial virus (RSV) (16%), HMPV (13%), and HBoV (5%). Together rhinoviruses, coronaviruses, HMPV, and HBoV accounted for 60% (65 of 109) of viruses. Although symptom scores and need for general practitioner (GP) consultations were highest in infants infected with RSV, they were similar in infants infected with other viruses. Viral shedding at 3 weeks occurred in 20% of cases. Rhinoviruses, coronaviruses, HMPV, and HBoV are common pathogens associated with respiratory symptoms in otherwise healthy infants. They should be considered in the differential diagnosis of the aetiology of ARI in this age group.The Pediatric Infectious Disease Journal 03/2008; 27(2):100-5. · 3.57 Impact Factor